Treatment of solid hydrocarbonaceous material



March 13, 1951 F. A. w. Ll-:FFER 2,544,843

TREATMENT oF soun ETnRocARBoNAcEoUs MATERIAL Filed Jan. 28, 1948 tivelycompact mass.

3 conjunction with the remaining features of the operation according tothe invention. The overall heat economy of the operation is not onlyfurthered by handling of the solid material in the nely divided state,but also by substantially complete avoidance of loss of sensible heatbetween the three principal stages of the process.

The attached drawing illustrates diagrammatically a suitable arrangementof an apparatus in which the process of my invention may be effected.

Finely divided oil shale or the like is supplied from a hopper I throughline 2 and valve 3 to an elevated portion of distillng retort 4,preferably to a point below the upper level of the solid materialtherein. The ilow of the solid from the hopper may be aided by aeratingthe solid material by means of a suitable gas supplied through line andvalve 6.

In retort 4, the solid is submitted to the distilling and strippingaction of highly heated gases and/or steam generated within the process,preferably in the absence of air or oxygen; the steam is supplied fromheating zone I (which is also a retort) through line 8 and valve 9 toone or more points at the lower portion of retort 4 and passes upwardlythrough the solid material moving downwardly through the retort eitherin a relatively compact mass or a fluidized dense phase.

Upon reaching the bottom of retort 4, the solid material issubstantially devoid of any volatilizable hydrocarbons and is permittedto flow through line I and valve I2 into transfer line I3 wherethroughit is moved with the aid of a gaseous medium to the combustion retortI4, to be introduced to the latter at an elevated point thereof. In thearrangement shown, the solid transferred through line I3 is passedthrough separator I5 wherein it is separated from the gaseous mediumwhereupon it moves downwardly under the force of gravity through line I6into combustion retort I4, wherein substantially all of the combustiblecontent of the uid particles is burned off. To elect the combustion, airis introduced into the lower portion of retort I4 through one or moreburner ports I1, I'I, or the like; these ports are designed to permitoperation of the retort i4 under any desired pressure and may also servefor the introduction of an auxiliary fuel during the starting up of theoperation or whenever auxiliary fuel may be desired for more eiectivelyoperating the process. The solid particles are preferably permitted topass downwardly through retort I4 in a relatively compact mass, althoughthe solid may be maintained in retort I4, in a iluidized dense mass, ifthis is .desirable and the particle size of the solid material is suchthat a nuidized dense phase will be obtained with the aid of such anamount of air as is required for substantially complete combustion ofthe combustible content of the solid.

The burned solid residue flows from the bottom of combustion retort i4through line I8 and valve I9, into heater 1, and is permitted to movedownwardly therethrough, preferably in a rela- During its downwardpassage, the highly heated solid is brought in contact with lowtemperature steam or with water, either of which may be introduced tothe bottom portion of heater 'I at one or more points thereof as throughline and valve 2l, and thereby a substantial or major portion of itsheat content is transferred to the water or steam, where- 4 by highlyheated or superheated steam is generated. This steam is discharged fromheater 'I vthrough line 8, and supplied at least in part as alreadydescribed, through Valve 9 to distilling retort 4. Any portion of thesteam not required for eecting or aiding in the retorting of the oilshale may be withdrawn through line 22 and valve 23 for use elsewhere.

Any gaseous medium may be used for transferring the retorted solidparticles from line Ill to combustion retort I4, but the heat economy ofthe process will be kept at an optimum degree of efliciency, andsubstantial loss of heat from the retorted solid will be avoided by useof the spent combustion gases issuing from the combustion retort I4through line 24. These hot combustion gases may be forced into line I3by means of blower 25, which discharges through lines 26 and 2I andvalve 28 into line I 3 at the junction of the latter with line l0.

The heat economy of the process will be further improved by precludingany substantial loss of heat from the highly heated non-combustiblesolid particles during their passage from combustion retort I4 to heater7. It is to be understood that all lines carrying hot streams of theaforesaid nature, as well as retorts 4 and I4 and heater I should beinsulated suciently to lpreclude substantial loss of heat by radiation.Insulation of retorts 4 and I4, and if desired, also of heater 'I, maybe applied internally whereby erosion and corrosion of the metallicvessel walls will be prevented or at least reduced to a minimum.

While not essential to the successful operation of the process, it maysometimes be desirable to supply a portion of the spent or oxygen-freecombustion gases from line 26 through valve 29 into line S andtherethrough into distilling retort 4. This supply of hot inert gases inaddition to the supply of more highly heated steam may, for example, aidin the maintenance of a `dense phase in retort 4, when the nely dividedsolid is sup- 'plied thereto in a relatively coarse particle sizerequiring a relatively large quantity of gaseous medium for themaintenance of a thoroughly agitated dense phase in retort 4.

While line 3 has been shown to discharge into separator I5, it may, ifso desired, terminate at an elevated point of combustion retort I4,preferably so as to discharge the distilled solid particles into saidretort I4 at a point below the upper level of the solid mass orfluidized dense phase therein. In this event, spent combustion gases notrequired for transfer of the solid through line I3 may be removed fromthe top of retort I4 through a line not shown, and through separator I5,to be discharged through line 33 and valve 3| to any suitable equipmentfor recovering heat from this gas stream.

Without departing from the general idea of countercurrent extractiontreatment of oil shale and the like with utilization of the combustiblematerials in the distillation-extraction residue for furnishing heat forthe process without use of any tubular or other conventional steamgenerators, the process may be modied by efecting the transfer of thesolidresidual material from distilling retort 4 to combustion retort I4,by means of a suitable mechanical conveying device. Similarly, withoutdeparting from the general concept of the process, the arrangement ofapparatus may be modified by superimposing distilling retort 4 oncombustion retort I4, and permitting the residual solid particles fromthe former to flow into the latter by gravity, substantially asdescribed with reference to `lthe flow through line I8 and valve I9. Insuch a modification, the highly heated solid residue from combustionretort I4 `may be transferred to heater I by mechanical means if saidheater Vis disposed substantially parallel to and at about the Samelevel as, instead of Vcoaxially with and below, retort I4. Thearrangement shown in the drawing is, however, preferable for mostpurposes. Alternatively, if s o desired, the distilling retort 4 may besuperimposed on the combustion retort and the distillation residuepermitted to flow by gravity through line I and valve I2 directly intothe upper portion of the combustion retort, while still retaining thearrangement of the combustion retort superimposed on the heater andcausing the combustion residue to f low by gravity into the heater. Thisparticular arrangement entirely dispenses with moving mechanical partscoming into contact with hot materials. But even when employing thearrangement as shown in the drawing, only a blower (25) for moving gasesat hightemperature will be required; and this does not entail the wearand tear and the operating difficulties encountered with moving partsexposed to high temperature during their employment for handling solids.

It is to be understood that aeration by a suitable gas such assuperheated steam taken from line 22 through valve 23 may be resorted tofor the purpose of decreasing the density and assisting the iiow of thematerial flowing through line I0 and/or line I8 in any one of theembodiments described.

It is also to be understood that any suitable means may be employed forsimultaneously assuring undisturbed withdrawal of the respective finelydivided solid materials from retorts 4, 'I, and I4 and substantiallyuniform distribution of the normally iuid media upon their introductionto these retorts. For example, when operating with the iinely dividedsolid material in any one of the retorts in a fluidized relatively densephase, a horizontal perforated plate may be disposed in the lower partof the retort and a gaseous fluid may be supplied thereto below theplate and distributed through the perforations into the fluidized densephase above the plate while a stream of solid particles of the materialundergoing treatment is withdrawn from the dense phase in the retort andfrom the retort itself through a standpipe terminating at a pointsomewhat above the perforated plate as diagrammatically indicated in thedrawing by broken lines with reference to the lower part of retort 4.Alternatively, when treating the finely divided solid material in anyone ofv the retorts 4, and I4 while said material passes downwardlytherethrough in a relatively compact mass or bed, the normally fluidmedium to be contacted with the finely divided solid material may beintroduced in an upward direction to the latter through a perforateddistributing member, such as is diagrammatically illustrated in thedrawing by broken lines with reference tothe lower part of retort 'I andwhich allows a free passageway for the descending solid partices to thewithdrawal.,

conduit provided at the bottom of the retort. Another suitable means forthis purpose consists ofan inverted perforated cone disposed above thebottom ofthe retort, gaseous fluid being supplied to the interspaeebetween the perforated cone and the retort bottom and'` finely-dividedsolid material being withdrawn from above then- 6 ver-ted leonedownwardly through a standpipe terminating in the apex of the-cone.

The vaporous distillation products liberated in dis-til'ling retort 4,are removed therefrom through line 32- teHsepar-ator 33, wherein theyare substantially freedv from solid particles, the latter being returnedto retort 4 by line 34, which penetrates to below the levelof therelatively compact mass of iluidized dense phase within retort 4. Thevaporous distillation products are thereupon conducted from separator 33through line 35 and valve 36 to suitable fractionation and condensingequipment for recovery of normally liquid and normally gaseous productfractions and for their separation from aqueous fluids comprising thewater resultingy from the condensation of the steam introduced to retort4. The fractionating and separating equipment may be of conventionaldesign and may be supplemented by chemicalA treating sections forremoving acidic components from the hydrocarbon fractions produced bytheY distillation of the oil shale or the like hydrocarbonaceousmaterials.

In the processasdescribed., the countercurrent flow of gaseous heating'medium and finely divided solid in retort 4 materially benefits theultimateV yields of the valuable hydrocarbon oil fractions desired asprimary product of the process and reduces to a minimum, undersirablecracking reactions which would result in excessive gas formation.Destructive distillation or cracking occurs to the desiredextent in thelower or hotter portion of the distilling retort While primarily anon-destructivey distillation takes place in the upper orrelatively-cool portion of this retort. Any portion of the gases formedduringthe distillation, particularly a relatively 'light portion thereofcomprising principally terial'to furnish the heatv requirements of theprocess. Y While the countercurrent flow treatment" has been includedabove as a benecial feature of the'r preferred'embodiment of theprocess, it will be evident from` the foregoing that thev invention isnot necessarily limited thereto and that it is an importantcharacteristicof' the invention in itsbroader aspects to effect thetreatment of finely divided oil shale and like-bituminous solidsofrelatively high non-combustible content duringy a continuous flowthrough three successive stagesl comprising distillingn the finelydivided solid bycontact in a distilling Zone with a highly heatedgaseous heat-carryingl medium compris'- ing Superheatedl steam producedvwithin-the process, supplying the hot finely divided distillationresidue toa combustionA zone and' thereinY burning substan-tiallylallundistilledfcombustibl'e materials from said distillation residuewhereby to impart' an increased heaty content, to the noncombusti-blevresidue, supplying thev hot finely dividedsolid residue fromthe'combustion. zone substantially without: intentional loss` of heat toalleati-ng zone andtherein abstracting heat from said solid residue andproducing super-heated steam-by contact of said residuefwith -anaqueousriiuiolsuchJ as water or low temperature. steam,

discharging the finely divi-dedV solid' residue from the heating zoneatr a substantially lowered temperature, amr supplying atleast a:portion. of

7 the superheated steam as highly heated-heatcarrying medium to thedistilling zone.

In carrying out the process the temperature distribution in thedistilling zone or retort Will depend largely on the initial compositionof the solid charge and in any event is to be sufficient to carbonizetarry components of the solid particles so as to permit the distillationresidue to f remain in iinely divided state for its transfer to thecombustion zone or retort. The process may be operated under anysuitable pressure and normally will be carried out at about atmosphericor a moderate superatmospheric pressure up to about atmospheres,although it may in some cases be desired to operate under higherpressure so as to permit relatively smaller dimensioning of theapparatus for a. given throughput of materials and also to permitobtaining steam under relatively high pressure. A further advantage inusing relatively high pressure residues in the avoidance of mechanicalconveying equipment for discharging the cooled solid residue from theheating retort or heater l. In general the pressure in the threeprincipal zones of treatment Will be approximately equalized except forsuch differential pressures as are necessary to assure adequate iiow ofsuperheated steam from the heater to the distilling retort.

In the normal operation of the process, Water is preferred to lowtemperature steam for supply through line 2n to heater 1. This procedurewill not only permit a maximum recovery of the heat content from thenon-combustible residue charged to the heater, but by the use of Waterin excess of the quantity required for steam generation the cooled solidresidue may be formed into a slurry and so removed from the bottomportion of heater 1 through line 3l and valve 3B. Water is thus used asa conveying medium for carrying the solid residue to a point of disposalor utilization outside the system. In this latter mode of operation aportion of the water used for the slurrying may be recovered bysettling, and returned to the heaterv to reduce the overall supply ofwater requirement of the process from an outside source.

The selection oi iineness of the particles charged to the distillingzone is dependent'to a large extent on economic considerations. Greateramounts of energy would be required for grinding to extreme neness, suchas 200 mesh or ner in the U. S. sieve series or about 0.075 mm. or lessin diameter, While a coarse particle size, such as 3 mesh or larger inthe U. S. sieve series or about 7 mm. or more in diameter, would rendermore diiiicult the transfer of the solid materials from the distillationzone to the combustion zone, and from the latter to the heating zone asWell as the discharge of the incombustible residue from the heating zoneto a suitable point of disposal. It is therefore preferred to opera theprocess in many instances with a medium particle size of less than 5 mm.diameter, the size being such that al relatively compact bed rather thana highly iluidized dense phase prevails in the distilling zone, yet thenon-combustible residue will be of suilicient fineness to permitslurrying out of the heating zone by means of Water. A particle size offrom approximately 0.1 to about 3.0 mm. diameter is preferred forcompact bed operations, while a particle size Within the approximaterange of 0.1 to 0.8 mm. diameter is preferred for fluidized dense phaseoperations.

In conventional oil shale distillation operations of the priorindustrial art Where the carbonized residue is utilized for generationof heat for the process, the carbonized residue is iirst quenched so asto permit handling in the open air and this quenching .constitutes asubstantial heat loss. In the present operation the carbonized residueis transferred directly, and while still hot to the combustion retortwhich as already described above may be accomplished advantageously bymeans of the hot combustion gases obtained from the combustion retort sothat an unduly elevated arrangement of the apparatus sections may beavoided. The overall heat economy of the process is further enhanced byavoidance of indirect heat exchange in the principal processing steps,and preferably by effecting the direct heat exchange in each of thethree principal process steps by -countercurrent flow.

In the operation of my process, the spent combustion gases from thecombustion retort are supplied to heat recovery. In the Working up ofrecovery of the distillation products in a Suitable recovery plant, asubstantial amount of heat is required and according to my invention lcontemplate the utilization for this purpose of the heat present in thespent combustion gases. A portion of the hot spent combustion gases may,moreover. be employed for drying oil shale or like material prior tosupplying such material to distilling retort 4. Such drying may beeffected after comminution of the solid charge, if so desired, and inany event, should be carried out in a manner assuring the maintenance ofthe solid material at temperatures below about 200 C. l

The principal source of heat in the distilling retort is the highlyheated gaseous heat-supplying medium supplied thereto from heater 'l ofthe system. In an operation in the manner herein described, the-countercurrent flow assures a minimum of cracking which will be lesswhen a relatively compact bed of the iinely divided solid is caused toflow downward, relative to an operation wherein a highly agitatedfluidized bed is employed in the distilling retort. In the relativelycompact, downwardly moving bed, a temperature gradient results with amaximum temperaturein the lowest, and a minimum temperature in thehighest portion of the distilling retort, so that volatile productsliberated at a relatively hot point of the retort will immediately passto a zone of lower temperature while at the same time they are dilutedwith more reiractory volatilized components which are liberated in theupper or cooler portions of the distilling retort, and with steam whichaids in avoiding or minimizing cracking reactions. The use of steam assubstantially the sole, or at least, the principal direct heat supplyingmediurn in the distilling retort, also has the advantage of enabling oneto separate the steam from the organic products insoluble in water bylayer separation upon its condensation in the recovery plant, and thusto avoid a dilution of the distillation products which would makediiiicult the recovery of the latter.

While it is herein indicated that it may sometimes be desirable tosupply a portion of the spent or oxygen-free combustion gases from thecombustion retort through the valve 2S to the distilling retort, it willbe understood from the foregoing that the preferred operation does notresort to this auxiliary supply of combustion gases to distilling retort5., and will operate solely with the supply of the high temperaturesteam thereto.

In accomplishing the desired distillation in the distilling retort, thetemperature and quantity of the steam will primarily depend on thenature and quantity of the solidY charge, and particularly on thecontent of the volatilizable organic compounds in the solid charge. As arule, a steam temperature of less than 650 C., and more particularly offrom 500 to 600 C. will be ample to eiect the distillation of most kindsof oil shale and torbanite at a suitable weight ratio of solid treatedto steam contacted therewith. Generally the maximum temperature of thesolid material in the distilling retort need not exceed 500 to 525 C.,and the temperature gradient may extend downwardly to about 300 C. butwill depend largely on the relative rates of throughput of solidmaterial and steam, and in the normal operation, the minimum temperatureof the vaporous and gaseous products issuing from the upper portion ofretort 4 through line S2, will be in the neighborhood of 400 to 450 C.This relatively high temperature is desirable for a maximum recovery ofhydrocarbon oils but may be kept lower when it is preferred to sacrificetotal yield of oil in order to obtain a relatively high yield of lowerboiling hydrocarbon oil fractions- In the latter case the highestboiling volatilizable components of the oil shale or other bituminoussolid will be retained in the distilling retort and will eventually becracked into lower boiling components and carbonaceous ornon-volatilizable residue.

In eecting the combustion of the undistilled combustible componentsretained in the distillation residue owingfrom distilling retort 4 tocombustion retort lf3, a controlling factor of operativeness is thesintering point of the ash constituents in the distillation residue. Ingeneral,

`sintering will be avoided as long as the temperature of the solidparticles does not exceed about '700 C. Combustion in the combustionretort can readily be accomplished effectively while the solid particlesare at temperatures between about 600 and 650 C., as the combustion isrendered uniform and substantially free from hot spots because of thecomminution and mobility of the solid particles in the present process.With some Voil shales, sintering will not occur until temperatures of800 C. or more are reached, and with materials of this nature,relatively high temperatures of the order of '200 to 750 C. may beemployed safely for the solid particles in the combustion retort. Airfor combustion may be supplied, if so desired, at a plurality ofsuperimposed regions in retort Il-l so as to preclude localizedoverheating. In general. only suiicient air should be supplied to thecombustion retort to eiTect substantially complete combustion ofthecombustible components and to obtaina substantially oxygenfree gas, thecompleteness of combustion being aided by the counterourrent flow ofcombustion gases and the nely divided solid which enters the combustionretort already at a temperature sufficient to support combustion. Thebest operation from the point of heat economy comprises the maintenanceof a combustion temperature just sufciently below the sinteri'ngtemperature of the incombustible residue to retain the latter in afreely flowing state whereby it will be possible to obtain a maximumsteam temperature in heater 1 upon supplying the highly heatedincombustible residue from combustion retort I4 to heater l. Likewise,the best operation from the point of yview of heat economy will comprisemaximum utilization of the heat `content of the hot incoml0 bustibleresidue by cooling it in heater 1 sufciently to permit its dischargefrom the bottom of the latter at a temperature below about C.

The process of my invention may be carried out under any desiredpressure. Only relatively small pressure differences are requiredbetween the 3 principal processing stagesl in order to maintain the ilowof solids therethrough. While relatively low pressure is preferable formaximum recovery of normally liquid hydrocarbons, it may be .preferablefrom the point of view of overall efficiency to maintain in the system apressure of the order of 10 to 15 atmospheres in order to have excesssteam under substantial. superatmospheric pressure available for use inthe recovery plant and in order to use the spent combustion gasesissuing from the vcombustion retort under the aforesaid pressure ofabout 10 to 15 atmospheres for the generation of power for use inhandling the raw oil shale or like bituminous solid while preparing itfor feeding to the system. It is evident that relatively little power isrequired for feeding the nely divided solid material under pressure toretort ll, and water under pressure to heater 1, so that a substantialbenefit will be obtainable when generating the spent combustion gasesunder pressure and then utilzing a portion of theV energy stored thereinfor power generation by means of turbines or the like.

In an alternative operation of my process, normally gaseoushydrocarbons, more particularly relatively refractoryhydrocarbon-containing gases such as natural gas or light fractionsthereof comprising methane and ethane, are supplied through line 20 toheater 'I in which heat is transferred from the non-combustible solidresidue of the shale to said gaseous hydrocarbons and theresultantheated gaseous hydrocarbons are directed through line 8 to.distilling retort 4. In the preferred embodiment of this operation,hydrocarbon gas fractions produced within the process and separated fromthe products discharged from distilling retort 4 through li-ne 35, andparticularly the methane and ethane fractions thereof, are employed asthe gaseous hydrocarbons supplied through line 20 to heater 1.

I claim as my invention:

1. A process for the treatment of solid hydrocarbonaceous material whichcomprises continuously supplying a stream of nely divided solidhydrocarbonaceous material of relatively .high ash content to a conneddistilling zone and passing it in a dense mass downwardly through saidzone in direct contact with a gasiform heatsupplying medium comprisingsuperheated steam at distilling temperature, withdrawing a stream of hotfinely divided distillation residue from said distilling zone andcommingling the same with a hot gaseous fluidizing medium, transferringsaid residue stream uidized in said gaseous fluidizing medium andsubstantially without intentional `cooling to a separate conn-nedcombustion zone and therein burning substantially all undistilledcombustiblematerial from said distillation residue while conducting thelatter in a densemass downwardly in direct contact with a freeoxygencontaining gas, introducing said superheated steam to the lowerportion of said distilling zone and said oxygen-containing gas to thelower portion of said combustion zone each at a ratey at which the solidmaterial in the dense masswithin each of said zones is maintained innely subdivided and freely flowing state, withdrawing a vaporous stream.of distillation products and gasiform heat-supplying medi-umfrom theupper porktion of said distilling zone while independently thereofdischarging hot combustion gases from the upper portion of said separatecombustion zone, passing a stream of highly heated noncombustibleresidue from said combustion zone substantially without intentionalcooling to a separate and confined heating zone and therein cooling saidnon-combustible residue by direct contact with water in an amount inexcess of that required to generate said superheated steam, continuouslyfeeding a stream of the resultant superheated steam from said heatingzone directly to said distilling zone, and discharging a slurry ofiinely divided solid residue and water at a substantially loweredtemperature from said heating zone.

2. A process for the treatment of oil shale which comprises continuouslysupplying a stream of oil shale divided into particles of less than mm.diameter and predominantly less than 3 mm. diameter to al confineddistilling zone and passing it in a relatively dense mass downwardlythrough said zone in direct contact with a gasiform heat-supplyingmedium comprising superheated steam at a sufficient temperature and insu'icient quantity to vaporize and expel substantially all distillablecomponents from said oil shale, withdrawing a stream of hot finelydivided distillation residue from said distilling zone and comminglingthe same with a hot gaseous fluidiz- 1 ing medium, transferring saidresidue stream fluidized in said gaseous fluidizing medium andsubstantiallyT without intentional cooling to a separate and confinedcombustion zone and therein burning substantially all undistilledcombustible material from said distillation residue while conducting thelatter in a relatively dense mass downwardly in direct contact with afree-oxygencontaining gas, introducing said superheated steam to thelower portion of said distilling zone and said oxygen-containing gas tothe lower portion of said combustion zone each at a rate at which thesolid material in the dense mass within each of said zones is maintainedin finely subdivided and freely flowing state, withdrawing a vaporousstream of distillation products and gasiform heat-supplying medium fromthe upper portion of said distilling zone while independently thereofdischarging hot combustion gases from the upper portion of said separatecombustion r zone, passing a stream of highly heated non-combustibleresidue from said combustion zone substantially without intentionalcooling to a separate and coniined heating zone and therein cooling saidnon-combustible residue by direct contact with water in an amount inexcess of that required to generate said superheated steam, continuouslyfeeding a stream of the resulting superheated steam to said distillingzone, with the temperature of said steam being substantially above themaximum temperature prevailing in the distilling zone, and dischargingfinely divided solid residue at a substantially lowered temperature in aslurry with said excess water from the lower portion of said heatingzone.

3. A process for the distillation of subdivided solid hydrocarbonaceousmaterial which comprises continuously supplying a stream of saidsubdivided material to a conned distillation zone and contacting itoountercurrently with a gasiform heat-supplying medium to distilvolatilizable hydrocarbons therefrom, transporting the resultant finelydivided solid distillation residue from said distillation zone to aseparate confined combustion zone by means of hot combustion gases,obtained as hereinafter set forth, supplying a gas containing freeoxygen to said combustion zone and therein burning substantially allundistilled combustible material from said residue while conducting thelatter downwardly countercurrently to the oxygen-containing gas,withdrawing a vaporous stream of distillation products andheat-supplying medium from said distillation zone, withdrawing hotcombustion gases from said combustion zone and supplying at least aportion of said hot combustion gases as the medium for transporting saiddistillation residue from the distillation zone to said combustion zone,introducing said gasiform medium to said distillation zone and theoxygen-containing gas to said combustion zone each at a rate at whichthe subdivided solid material in the descending mass within each of saidzones is maintained in a finely divided and freely flowing state,passing a stream of highly heated non-combustible residue from saidcombustion zone substantially without intentional cooling to a separateand confined heating zone and therein cooling said non-combustibleresidue by direct contact with a uid heat-carrying medium substantiallydevoid of free oxygen, continuously feeding a stream of resulting highlyheated gasiform heatcarrying medium from said heating zone as saidheat-supplying medium directly to said distilling zone, and discharginga stream of finely divided solid residue at a substantially loweredtemperature from said heating zone.

4. A process for the distillation of finely subdivided solidhydrocarbonaceous material which comprises continuously supplying astream of said nely subdivided material to a confined distillation zoneand contacting it countercurrently with a gasiform heat-supplying mediumto distil volatilizable hydrocarbons therefrom, transporting theresultant finely divided solid distillation residue in a iuidized streamfrom said distillation zone to a separate conned combustion zone bymeans of hot combustion gases, obtained as hereinafter set forth,supplying a gas containing free oxygen to said combustion zone andtherein burning substantially all undistilled combustible Vmaterial fromsaid residue while conducting the latter downwardly countercurrently tothe oxygen-containing gas, withdrawing a vaporous stream of distillationproducts and heat-supplying medium from said distillation zone,withdrawing hot combustion gases from said combustion zone and supplyingat least a portion of said hot combustion gases as the uidizing mediumfor transporting said distillation residue from said distillation zoneto said combustion zone, introducing said gasiform medium to saiddistillation zone and the oxygen-containing gas to said combustion zoneeach at a rate at which the subdivided solid material in the descendingmass within each of said zones is maintained in a hindered settling andfreely flowing state, passing a stream of highly heated non-combustibleresidue from said combustion zone substantially without intentionalcooling to a separate and conned heating zone and therein cooling saidnon-combustible residue by direct contact with Y an aqueous uid,continuously feeding a stream of resulting superheated steam as the soleheatsupplying medium from said heating zone directly to said distillingzone, with the temperature of said steam being substantially above themaximum temperature prevailing in the distilling Zone, and discharging astream of finely divided solid residue at a substantially loweredtemperature from said heating `zone.

5. A process for the distillation of subdivided oil shale whichYcomp-rises continuously supplying a stream of said subdivided shaleparticles of not more than about 0.8 mm. diameter to a confineddistillation zone and contacting it counter-currently with a gasi-forinheat-supplying medium comprising superhea-ted steam to distilvolatiliz.- -able hyd'rocarbons'therefrom, transporting the resultantfinely divided solid distillation residue in a fluidized stream fromsaid distillation zone to a separate and confined combustion zone bymeans of 'hot combustion gases, obtained as hereinafter set forth,Vsupplying a gas containing free oxygen to said combustion zone andtherein burning substantially all undistilled combustible material fromsaid residue While conducting the latter downwardly co-untercurren-tlyto the oxygen containing gas, withdrawing a vaporous stream ofdistillation products and heat supplying medium from said distillationzone, withdrawing hot combustion gases from said combustion zione andsupplying at least a portion of `liad hot combustion gases Las thefluidizing medium for transporting said distillation residue from saiddistillation zone to said combustion zone, introducing said superheatedsteam to said distillation zone and the oxygen containing gas to saidcombustion zone each at a rate at which l the subdivided solid materialin the descending mass within each of said zones is maintained in ahindered settling and freely flowing state, passing a stream of highlyheated non-combustible residue from said combustion zone substantiallywithout intentional cooling to a separate and confined heating zone andtherein cooling said non-combustible residue by direct contact with anaqueous fluid, continuously feeding a stream of resulting superheatedsteam as the sole heatsupplying medium from said heating zone directlyto said distilling zone, with the temperature of said steam beingsubstantially above the maximum temperature prevailing in thedistillation zone, and discharging finely divided solid residue at asubstantially lowered temperature in a slurry stream from said heatingzone.

6. A process for the distillation of oil shale which comprisescontinuously supplying a stream of oil shale subdivided into particlessubstantially of from 0.1 to 0.8 mm, diameter to a confined distillationzone and passingit in a fluidized dense phase downwardly through saidzone in countercurrent flow to and in direct contact with a gasiformheat supplying medium comprising steam superheated to a temperature offrom about 500 C. to about 650 C. and at a pressure of from aboutatmospheric to about 15 atmospheres in sufcient quantity to vaporize andexpel substantially all distillable components of said oil shale,transporting the resultant finely divided distillation residue in auidized stream from said distillation zone to a separate and confinedcombustion zone by means of hot combustion gases, obtained ashereinafter set forth, supplying a gas containing free oxygen tosaidcombustion zone and therein burning substantially all undistilledcombustible material from said residue while conducting the latter in adense fluidized phase downwardly in countercurrent flow to theoxygen-containing gas, withdrawing a vaporous stream of distillationproducts and heat-supplying medium from said distillation zone,withdrawing hot combustion gases from said combustion zone and supplyingat least a portion of 14 said combustion gases as the uidizing mediumfor transporting said distillation residue from the distillation zone tosaid combustion zone, introducing vsaid superheated steam to saiddistillation vrone and the oxygen-containing gas to said combustion zoneeach at a rate at which the solid material in the dense phase withineach of said zones is maintained 'in a hindered settling a-nd freelyflowing state, passing a stream of highly heated non-combustible residuefrom said combustion zone substantially without intentional `cooling toa separate and confined heating zone and therein cooling saidnon-combustile residue by direct contact with' an aqueous duid,

`continuously feeding a stream of resulting superyheated steam as thesole heat-supplying medium from said heating zone to said distillationzone, and discharging from said heating zone the finely divided solidresidue at a substantially lower temperature Vand in a slurry streamprovided by an unvaporized portion -of said aqueous fluid.

7. A process for the distillation of subdivided lsolid hydrocarbonaceousmaterial which comprises: contacting said material in a distillationZone with a gaseous heat-supplying medium to distil volatilizablehydrocarbons therefrom; transporting the resultant solid distillationresidue by means of hot combustion gases, obtained as hereinafterdescribed, to an independent combustion zone; supplying anoxygen-containing gas to said combustion zone and therein burningcombustible material from said distillation residue; withdrawing hotcombustion gases and hot non-combustible residue from said combustionzone; supplying at least a portion of said hot combustion gases as thetransfer medium to transport said distillation residue from saiddistillation zone to said combustion zone; contacting said hotnon-combustible residue in an independent heat exchange zone with afluid medium to convert the latter into said gaseous heatsupplyingmedium; and introducing said gaseous heat-supplying medium into saiddistillation zone.

8. A process for the distillation of subdivided solid hydrocarbonaceousmaterial which comprises: contacting said material in a distillationzone with superheated steam to distil volatilizable hydrocarbonstherefrom; transporting the resultant solid distillation residue bymeans of hot combustion gases, obtained as hereinafter described, to anindependent combustion Zone; supplying an oxygen-containing gas to saidcombustion zone and therein burning combustible material from saiddistillation residue; withdrawing hot combustion gases and hot non-comfbustible residue from said combustion zone; supplying at least a portionof said hot combustion gases as the transfer medium to transport saiddistillation residue from said distillation Zone to said combustionzone; contacting said hot noncombustible residue in an independent heatexchange zone with an aqueous fluid to convert the latter into saidsuperheated steam; and introducing said superheated steam into saiddistillation zone. ,c

9. A process for the distillation of subdivided solid hydrocarbonaceousmaterial which comprises: introducing said material to the upper portionof a confined distilling zone and therein contacting it with a gaseousheat-supplying medium to distil volatilizable hydrocarbons therefrom,withdrawing a stream of resultant solid distillation residue from thelower portion of said 75 distilling zone and commingling the same with agaseous iiuidizing medium comprising hot combustion gases obtained ashereinafter set forth, transferring said residue stream fluidized insaid gaseous medium to a separate conned combustion zone, supplying anoxygen-containing gas to said combustion zone and therein burningcombustible material from said distillation residue, introducing saidgaseous heat-supplying medium to the lower portion of said distillingzone and said oxygen-containing gas to the lower portion of saidcombustion Zone each at a rate at which the solid material within eachof said zones is maintained in finely subdivided and freely flowingstate, withdrawing a vaporous stream of distillation products andgasiform heat-supplying medium from the upper portion of said distillingzone while independently thereof discharging hot combustion gases fromthe upper portion of said separate combustion zone, I

16 REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 1,524,784 Bartolomeis Feb. 3,19251,836,051 Trumble Dec. 15, 1931 1,901,169 Karrick Mar. 14, 19331,509,667 Catlin Sept. 23, 1924 1,950,558 Karrick Mar. 13, 19341,953,040 Brandegee Mar. 27, 1934 1,983,943 Odell Dec. 11, 19341,984,380 Odell Dec. 18, 1934 2,167,099 Benezech July 25, 1939 2,366,057Russell Dec. 26, 1944 2,409,797 Roetheli Oct. 22, 1946 2,414,586 EgloffJan. 21, 1947 2,432,135 Barr Dec. 9, 1947 FOREIGN PATENTS Number CountryDate 283,259 Great Britain Jan. 2, 1928 286,404 Great Britain Mar. 8,1928 419,444 Great Britain Nov. 8, 1934 484,050 Great Britain July 12,1937 487,983 Great Britain June 29, 1938

1. A PROCESS FOR THE TREATMENT OF SOLID HYDROCARBONACEOUS MATERIAL WHICHCOMPRISES CONTINUQUSLY SUPPLYING A STREAM OF FINELY DIVIDED SOLIDHYDROCARBONACEOUS MATERIAL OF RELATIVELY HIGH ASH CONTENT OF A CONFINEDDISTILLING ZONE AND PASSING IT IN A DENSE MASS DOWNWARDLY THROUGH SAIDZONE IN DIRECT CONTACT WITH A GASIFORM HEATSUPPLYING MEDIUM COMPRISINGSUPERHEATED STREAM AT DISTILLING TEMPERATURE, WITHDRAWING A STREAM OFHOT FINELY DIVIDED DISTILLATION RESIDUE FROM SAID DISTILLING ZONE ANDCOMMINGLING THE SAME WITH A HOT GASEOUS FLUIDIZING MEDIUM, TRANSFERRINGSAID RESIDUE STREAM FLUIDIZED IN SAID GASEOUS FLUIDIZING MEDIUM ANDSUBSTANTIALLY WITHOUT INTENTIONAL COOLING TO A SEPARATE CONFINEDCOMBUSTION ZONE AND THEREIN BURNING SUBSTANTIALLY ALL UNDISTILLEDCOMBUSTIBLE MATERIAL FROM SAID DISTILLATION RESIDUE WHILE CONDUCTING THELATTER IN A DENSE MASS DOWNWARDLY IN DIRECT CONTACT WITH A FREEOXYGENCONTAINING GAS, INTRODUCING SAID SUPERHEATED STREAM TO THE LOWERPORTION OF SAID DISTILLING ZONE AND SAID OXYGEN-CONTAINING GAS TO THELOWER PORTION OF SAID COMBUSTION ZONE EACH AT A RATE AT WHICH THE SOLIDMATERIAL IN THE DENSE MASS WITHIN EACH OF SAID ZONES IS MAINTAINED INFINELY SUBDIVIDED AND FREELY FLOWING STATE, WITHDRAWING A VAPOROUSSTREAM OF DISTILLATION PRODUCTS AND GASIFORM HEAT-SUPPLYING MEDIUM FROMTHE UPPER PORTION OF SAID DISTILLING ZONE WHILE INDEPENDENTLY THEREOFDISCHARGING HOT COMBUSTION GASES FROM THE UPPER PORTION OF SAID SEPARATECOMBUSTION ZONE, PASSING A STREAM OF HIGHLY HEATED NONCOMBUSTIBLERESIDUE FROM SAID COMBUSTION ZONE SUBSTANTIALLY WITHOUT INTENTIONALCOOLING TO A SEPARATE AND CONFINED HEATING ZONE AND THEREIN COOLING SAIDNON-COMBUSTIBLE RESIDUE BY DIRECT CONTACT WITH WATER IN AN AMOUNT INEXCESS OF THAT REQUIRED TO GENERATE SAID SUPERHEATED STEAM, CONTINUOUSLYFEEDING A STREAM OF THE RESULTANT SUPERHEATED STREAM FROM SAID HEATINGZONE DIRECTLY TO SAID DISTILLING ZONE, AND DISCHARGING A SLURRY OFFINELY DIVIDED SOLID RESIDUE AND WATER A A SUBSTANTIALLY LOWEREDTEMPERATURE FROM SAID HEATING ZONE.